Four complementary aspects of the control of articulatory movements will be compared in normal subjects and patients with apraxia of speech. 1. Study of duration of speech segments and of amplitudes and velocities of articulator movements will indicate the relation between apractics and normal subjects in basic articulatory dynamics; 2. Study of coarticulation in lip, mandible and velar movement will illustrate apractic ability at advanced planning, and termination of movements; 3. Compensatory articulation in the presence of bite blocks will indicate the apraxics ability at rapid reorganization of articulatory patterns; 4. Pursuit tracking using different parts of the speech and nonspeech motor system and different sensory modalities will indicate the specificity of the apractic deficit in terms of motor subsystems, sensory modalities, and sensorimotor integration. By beginning the direct observation of articulatory movements of speech apractics we hope to go considerably beyond present, imprecise, perceptually-based characterizations of apraxia of the speech musculature. We hope that such an improved characterization will lead to more effective differential diagnosis of apractics, and will guide the choice of more specific remedial procedures.